Determination of the carboxyl termini of proteins with ammonium thiocyanate and acetic anhydride, with direct identification of the thiohydantoins

Biochemistry ◽  
1969 ◽  
Vol 8 (12) ◽  
pp. 4735-4740 ◽  
Author(s):  
Laurence D. Cromwell ◽  
George R. Stark
Keyword(s):  
Acetic Anhydride ◽  
Ammonium Thiocyanate ◽  
Direct Identification

DETERMINATION OF ALDOSTERONE AND DEOXYCORTICOSTERONE IN PLASMA USING 3H-ACETIC ANHYDRIDE AND VAPOUR PHASE ACETYLATION

1969 ◽  
Vol 61 (1_Suppl) ◽  
pp. S12 ◽  
Author(s):  
V. H. T. James ◽  
A. E. Rippon ◽  
M. L. Arnold
Keyword(s):  
Acetic Anhydride ◽  
Vapour Phase

Infrared Quantitative Analysis of Mixtures Containing Isopropenyl Stearate, Stearic Acid, Stearic Anhydride, and Mixed Stearic—Acetic Anhydride

1972 ◽  
Vol 26 (1) ◽  
pp. 96-99 ◽  
Author(s):  
Mary Jo Calhoun ◽  
Edward S. DellaMonica
Keyword(s):  
Acetic Anhydride ◽  
Stearic Acid ◽  
Relative Concentration ◽  
Ternary Systems ◽  
Spectral Interference ◽  
Complex Mixtures ◽  
Ratio Method ◽  
Baseline Method ◽  
Binary And Ternary Systems

A method for the determination of individual components of complex mixtures is presented. The technique used is based on ir-absorbance measurements for stearic acid at 1700 and at 935 cm−1 when the concentration range exceeds 0.50% wt/vol; for isopropenyl stearate at 1145 and at 865 cm−1; for stearic anhydride at 1030 cm−1 and mixed stearic-acetic anhydride at 1000 cm−1. The baseline method was used in all absorbance measurements. Absorbance-concentration relationships obeyed Beer's law from 0 to 2.0% wt/vol for most compounds; the exception being stearic acid (at 1700 cm−1), where linearity was limited to a maximum 0.50% wt/vol. Due to spectral interference between the two anhydrides at low concentration ratios, an empirical percent transmission ratio method was used to estimate the relative concentration of each. Binary and ternary systems were studied and the standard deviations of the differences between theoretical and calculated values indicate that this method is reliable.

Gas-Liquid Chromatographic Identification and Determination of Alkanolamines. I. Application to Aerosol Hair Sprays

1971 ◽  
Vol 54 (5) ◽  
pp. 1175-1178
Author(s):  
Margaree H Champion ◽  
John H Jones
Keyword(s):  
Acetic Anhydride ◽  
Diethylene Glycol ◽  
Glycol Succinate ◽  
Diethylene Glycol Succinate ◽  
Liquid Chromatographic

Abstract Alkanolamines, in the absence of water, are converted to the amide ester or triacetate with acetic anhydride-pyridine mixture. The amide ester or triacetate of the alkanolamine is determined by GLC on a column containing diethylene glycol succinate on Chromosorb G. Procedures for determining alkanolamines in various hair sprays are described; recoveries by the proposed procedure were satisfactory. The method developed was applied to the following 4 alkanolamines: 2-amino-2-methyl-1-propanol, 2-amino-2-methyl-1,3-propanediol, 2-amino-2-ethyl-1,3-propanediol, and triisopropanolamine.

scholarly journals Determination of GTN Model Parameters Based on Artificial Neutral Network for a Ductile Failure

2021 ◽  
Vol 2 (1) ◽  
pp. 01-05
Author(s):  
YASSINE CHAHBOUB ◽  
SZAVAI Szabolcs
Keyword(s):  
Ductile Failure ◽  
Compact Tension ◽  
Model Parameters ◽  
Single Edge ◽  
Direct Identification ◽  
Simulation Data ◽  
Short Period ◽  
Artificial Neural Network Ann ◽  
Excellent Tool

The Gurson – Tvergaard – Needleman (GTN) mechanical model is widely used to predict the failure of materials based on laboratory specimens, direct identification of Gurson – Tvergaard – Needleman parameters is not easy and time-consuming, and the most used method to determine them is the combination between the experimental results and those of the finite elements, the process consists of repeating the simulations several times until the simulation data matches the experimental data obtained at the specimen level.This article aims to find GTN parameters for the Compact Tension (CT) and Single Edge Tensile Test (SENT) specimen based on the Notch Specimen (NT) using the Artificial Neural Network (ANN) approach. . This work presents how the ANN could help us determine the parameters of GTN in a very short period of time. The results obtained show that ANN is an excellent tool for determining GTN parameters.

scholarly journals Determination of Peroxide Value in Sunflower Halva using a Spectrophotometric Method

2010 ◽  
Vol 67 (2) ◽  
Author(s):  
Vlad MURESAN ◽  
Sevastita MUSTE ◽  
Emil RACOLTA ◽  
Cristina Anamaria SEMENIUC ◽  
Simona MAN ◽  
...  
Keyword(s):  
Peroxide Value ◽  
Room Temperature ◽  
Lipid Fraction ◽  
Ammonium Thiocyanate ◽  
Storage Conditions ◽  
Complexing Agent ◽  
Root Extract ◽  
Sunflower Seeds ◽  
The One

Sunflower halva, popular in countries from Eastern Europe, is made of sunflower tahini, cooked sugar and soapwort root extract. Lipid fraction in traditional sunflower halva is rich in polyunsaturated fatty acids, susceptible to peroxidation. Oxidation of the lipids is one of the main causes of lipid rich food deterioration leading to formation of off-flavour that negatively affect their quality and shelf life. In this study the initially phase of oxidation in sunflower halva was assessed, using as indicator the peroxide value (PV). The protocol followed was the one described by IDF standard which uses ammonium thiocyanate as Fe(III)-complexing agent. Halva samples stored at room temperature, in open air conditions for four months, respectively ten months were analyzed. The PV of sunflower halva at 10 months of storage was ~ 2 times higher that the PV of sunflower halva at 4 months of storage. The samples of sunflower seeds used for the analysis were freshly dehulled and dehulled and then stored at room temperature in open air conditions for four months. The freshly dehulled sunflower seeds had a PV of 4.14 meq O2/Kg fat, similar values with those reported in the literature. The sunflower seeds dehulled and than stored for 4 months at room temperature in open air conditions had a PV of 89.47 meq O2/Kg fat, rancid taste being detected. Regarding the oxidative stability of sunflower halva, care must be taken on storage conditions and packaging – temperature and oxygen availability. For further studies addition of supplementary antioxidants should be considered.

Colorimetric and Gas-Liquid Chromatographic Determination of Atropine-Hyoscyamine and Hyoscine (Scopolamine) in Solanaceous Plants

1975 ◽  
Vol 58 (5) ◽  
pp. 884-887
Author(s):  
Mohamed S Karawya ◽  
Samia M Abdel-Wahab ◽  
Mohamed S Hifnawy ◽  
Mohamed G Ghourab
Keyword(s):  
Citric Acid ◽  
Acetic Anhydride ◽  
Thin Layer ◽  
Chromatographic Determination ◽  
Chromatographic Procedure ◽  
Liquid Chromatographic Determination ◽  
Solanaceous Plants ◽  
Liquid Chromatographic ◽  
Colorimetric Methods

Abstract Two colorimetric micromethods are described for the determination of atropine-hyoscyamine and hyoscine (scopolamine), using p-dimethylaminobenzaldehyde and citric acid-acetic anhydride as the color reagents. These methods are sensitive to 60-1200 and 10-360 μg alkaloid/10 ml. The colorimetric methods were also successfully applied after a preliminary thin layer chromatographic separation of the alkaloids. A gasliquid chromatographic procedure was also developed, which yielded comparable results with the colorimetric methods.

Collaborative Study of the Gas-Liquid Chromatographic Determination of Sorbitol in Bakery Products

1973 ◽  
Vol 56 (1) ◽  
pp. 66-67
Author(s):  
Harvey K Hundley
Keyword(s):  
Aqueous Solution ◽  
Acetic Anhydride ◽  
Collaborative Study ◽  
Chromatographic Determination ◽  
Bakery Products ◽  
Sugar Alcohols ◽  
Flame Ionization ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A GLC method for the determination of sorbitol has been collaboratively studied. Sugar and sugar alcohols are extracted from the bakery products by methanol and the solvent is evaporated. Acetate derivatives are then formed by addition of acetic anhydride in pyridine, and the derivatives are extracted from an aqueous solution with chloroform and analyzed by flame ionization GLC. Collaborative results show a recovery ranging from 90 to 102% sorbitol from bakery products containing 1.5 to 7% sorbitol. The method has been adopted as official first action.

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